Inside the single-story center in west suburbanSt. Charles, the mood remained calm amid the muted conversations as on-duty dispatchers braced themselves for the next crisis call.

"We get calls from parking complaints and barking dogs and then you have the extremes — suicides, shootings, homicides — everything you hear on the news," said Jim Jones, training coordinator for Tri-Com, which serves Batavia, Elburn, Geneva and St. Charles.

Many emergency dispatchers are drawn to the variety and challenge of their work — not to mention the satisfaction that comes with helping distraught callers. But the stress can take a toll on some, according to a recently published Northern Illinois University study, which found that handling traumatic calls — suicide attempts, abused children, fatal shootings, serious car wrecks and the like — could have serious mental health consequences.

"Dispatchers frequently have pretty strong emotional reactions to the phone calls they handle," said Michelle Lilly, NIU psychology professor and co-author of the report, which appeared in the March 29 issue of the Journal of Traumatic Stress. "Our sample reported just as much emotional distress and reaction to (traumatic) calls as police officers have."

Believed to be the first study to zero in on the incidence ofpost-traumatic stress disorderamong dispatchers, it was conceived by co-author Heather Pierce, Lilly's former student and a onetime west suburban dispatcher who's now an NIU psychology department researcher.

For the study, Pierce and Lilly recruited 300 dispatchers from across the country to participate, and 171 from 24 states responded. They were predominantly middle-aged Caucasian females with more than a decade of experience apiece, the researchers said.

Participants were asked about the types of traumatic calls they handled and the resulting stress. They also rated the most distressing kind of call and the worst they personally handled.

The worst calls were the unexpected death or injury of a child (16.4 percent), suicidal callers (12.9 percent) and shootings involving police officers or the unexpected death of an adult (9.9 percent each).

Study respondents experienced "one or two symptoms" of PTSD while as many as 3.5 percent had symptoms serious enough to qualify for a full PTSD diagnosis.

"There are certainly folks out there who are struggling with some pretty serious mental health conditions that they attribute to trauma exposure," Lilly said. "What we know about trauma is that it tends to mount and have a cumulative effect. The more trauma you're exposed to and the longer you're emotionally distressed, the harder it is for your body mentally and physically."

The Washington-based American Psychological Association defines PTSD as an anxiety problem that develops after extremely traumatic events. It is often associated with combat veterans or frontline emergency personnel.

"People with PTSD may relive the event via intrusive memories, flashbacks and nightmares," according to a definition in the APA's Encyclopedia of Psychology. "(They) avoid anything that reminds them of the trauma and have anxious feelings they didn't have before that are so intense their lives are disrupted."

Dispatchers are the first responders whenever anyone calls 911. They must calmly collect information from sometimes distraught callers, visualize the scene, determine the seriousness of the situation and then marshal appropriate emergency resources while also juggling multiple lines of communications.

And after a call is complete, there's often no letup.

"When you hang up on that caller or you're done with that radio transmission, you have to move on," said Pierce, who started as an emergency medical technician, spent five years as a Kendall County dispatcher/tele-communicator and then worked at Tri-Com for five years.

"The phone's going to ring again and there's going to be another event. There's no time to process what happened (in a previous call). It is difficult," Pierce said.

It takes a strong personality to work as a dispatcher. Self-reliance, assertiveness and ability to multitask are critical skills.

"You need a Type A personality," said Tracie Whalen, a lead operator and supervisor now in her 20th year at Aurora's call center. "You pretty much have to run yourself. ... People who aren't confident in themselves, who question their own abilities, do not do well."

Still, even the veterans can be affected on a particularly bad day at the center, which has six people working a midday shift.

"The worst days are kids days," Whalen said. "We had a day where we lost three kids in a shift. That was a bad day. (But) you have to see the big picture: What can I do to help from here and calm the person down to where you can get (the information) you need?

"After the call's over, you can go outside and have your cry," she said. "It gets to you, but the trick is not to let it get to you when you need to do something."

Lengthy and excessive training helps weed out some problematic applicants even before a dispatcher first plugs in a headset.

"Our training program is 27 weeks," Tri-Com's Jones said. "A trainee does not do anything on their own for their first six months of employment without being monitored. (Even then) the success rate is 50-50 because of the stress involved and the type of work."

Aurora and Tri-Com personnel say there's a close-knit atmosphere and they can lean on each other for support. More agencies now offer a wide range of after-incident debriefings and counseling.

And some, like Pierce, also have a built-in support system at home.

"I am married to a police officer, so I always had someone to debrief with that was in the field and I could talk to," she said.

But Lilly said there's still a need to raise consciousness in the larger law enforcement and emergency response community.

"(Agencies should encourage) discussion among dispatchers about the stresses of the job and how they handle it, and provide intervention services for individuals who have had upsetting calls," she said.

Police officers and firefighters often participate in debriefing sessions after traumatic cases. "It might be helpful for dispatchers to be included in those debriefings so they know what happened and can talk about their reactions," Pierce said.